Process for the preparation of 7-(D-2-amino-2-(1,4-cyclo-hexadienyl) acetamido) desacetoxycephalosporanic acid and 7-(D-2-amino-2-(1,4-cyclohexadienyl) acetamido) cephalosporanic acid

ABSTRACT

Processes for the preparation of 7-(D-2-Amino-2-(1,4cyclohexadienyl)acetamido)desacetoxycephalosporanic acid and 7(D-2-Amino-2-(1,4-cyclohexadienyl)acetamido)cephalosporanic acid are described utilizing N-(2,2,2-trichloroethyloxy- or t-butoxycarbonyl)-D- Alpha -dihydrophenylglycine and 7aminodesacetoxycephalosporanic acid, 2,2,2-trichloroethyl or tbutyl ester or 7-aminocephalosporanic acid, 2,2,2-trichloroethyl or t-butyl ester, respectively.

United States Patent Diassi et a].

[4 1 Oct. 14,1975

Assignee:

PROCESS FOR THE PREPARATION OF 7-[D-2-AMINO-2-(1,4-CYCLO-HEXADIENYL)ACETAMIDO] DESACETOXYCEPHALOSPORANIC ACID AND7-[D-2-AMINO-2-(1,4-

V CYCLOHEXADIENYL)ACETAMIDO] CEPHALOSPORANIC ACID Inventors: PatrickAndrew Diassi, Westfield,

NJ Manmohan Singh Atwal, New York, NY.

E. R. Squibb & Sons, Inc., Princeton, NJ.

Filed: Feb. 16, 1973 App]. No.: 333,096

US. Cl. 260/243 C; 424/246 Int. Cl. C09D 501/20 Field of Search..260/243 C, 239.1

References Cited UNITED STATES PATENTS 1 H1967 Crast et a1.. 260/243 C3,485,819 12/ 1969 Weisenbum et al. 260/243 C 3,539,562 11/1970 Diassiet a1 3,549,628

Priniary ExaminerNicholas S. Rizzo Attorney, Agent, or FirmLawrence S.Levinson; Merle J. Smith; Stephen B. Davis 71 ABSTRACT Processes for thepreparation of 7-[D-2-Amino-2-( 1,4-

7 Claims, No Drawings 12/1970 Chauvette .11. 260/243 c cleavage or bothPROCESS FOR THE PREPARATION OF 7-(D-2-AMINO-2-( 1,4-CYCLO-HEXADIENYL)ACETAMIDO) DESACETOXYCEPHALOSPORANIC ACID AND 7-(D-2-AMINO-2-(1,4-CYCLOl-IEXADIENYL) 2 wherein Z is as previously described; X and Xare (CH C- or Cl CCH with the provision that X and X can not both be (CHC simultaneously, and R is lower alkyl.

5 In addition, this invention is intended to encompass ACETAMIDO)CEPHALOSPORANIC ACID the useful intermediates of this invention, that iscompounds of the formula VI wherein Z is as previously de- SPECIFICATIONscribed, X is Cl CCl-l and X is H, (CH C- or In the continuing search toprepare improved antibi- C CH recently CQmPOUIIdS have p p In thisinvention, the terni lower alkyl is intended to having excellentantimicrobial properties which are the mean a i h or b h d hydrocarbongroup of subject of U.S. Pat. No. 3,485,819, issued Dec. 23, from 1 to 7carbon atoms; 1969. These compounds have the following structure: Thecompounds f the structure [11 prepared y the reaction of t-butylchloroformate or 2,2,2- '1? i Y 15 trichloroethyl chloroformate withD-l,4-cyclohexadi- CH- c-NH I --r en-l-yl-glycine. The preparation ofcompounds III and H2 IV, wherein X is (CH C is described in Journal of NMedicinal Chemistry 14(1971) 117.

(3421 The process of this invention relates to the reaction C02" ofcompounds of the type IV with compounds of the I i l type V, wherein Xis (CI-I C or CI CCI-I and X is wherein Z is hydrogen (I) or acetoxy(II). In the case CI CCH to give compounds of the structure VI. Thiswhere is hydroge the preferre ompo is reaction is accomplished by theinitial use of three solua-a l ,4- y l hexad -ltions: l a lower alkylhaloformate in an anhydrous orylacetamido)desacetoxycephalosporanic acidP ganic solvent, e.g., methyl chloroformate in anhydrous (line) Whilewhen Z is acewxy, h Preferred dimethoxyethane, diethyl ether ortetrahydrofuran, (2) Pound is D-wy h the compound of the type V in anorganic solvent, such y P P acid as dimethoxyethane, diethyl ether orpreferably tetra- ThIS invention relates to a method for the convenienthydrofuran and (3) the compound f the type v an Producnon 9 these usFfulantimicmbialsorganic solvent, such as dimethoxyethane, diethyl etherMore specifically, this invention relates to the followor tetrahydmfuranand an acid acceptor Such as mg Syntheuc route: dium bicarbonate,trimethylamine or triethylamine acreductive cleavage, hydrolysis or bothhydrolysis, reductive 4 companied by a catalytic amount of a strongorganic base, such as benzyldimethylamine, dibenzylmethylamine, orp-methoxybenzlamine.

While organic ethers are the preferred solvents, aromatic hydrocarbons,such as toluene, hydrocarbons, such as 3-methylpentane, halogenatedhydrocarbons such as chloroform and carbon tetrachloride or otherstandard solvents such as dimethylformamide may be used. In choosing asolvent, one need only require that the solvent remain a liquid at thetemperature the reaction is to be run at, that the solvent be inert tothe reac tants, and that it'at least partially dissolve the reactants.The reaction is generally conducted from about 10 to about 50C,preferably 25C for from about 30 minutes to about 12 hours, preferably 4hours. v

volved in the systematic removal of the protective groups (Cl CCl-l and(CH C) from the compounds of the type'Vl-wherein Z is as previouslydescribed, X is hydrogen,(CH C or Cl CCH and X is hydrogen, CI CCH or(CH -;C with the provisio that at least one group is Cl,CC1-l When bothX and X are Cl CCl-l the. bistrichloroethyl compounds are converted tocompounds I and [1 by being dissolved in about 90 percent aqueous formicacid at'from about 0 to about 10C, and to this solution, zinc dust(about three to about ten times the weight of bistrichloroethylcompound) is added slowly. Depending upon the rate of stirring,efficiency of cooling (heat transfer), etc., one must alter the rate ofaddition and length of stirring after the addition is,35 complete toinsure complete reaction. However, in typical laboratory scalepreparations, addition periods of from 3 to 15 minutes coupled with anadditional 15 minutes to about 4 hours to permit the reaction to go tocompletion are generally adequate.

When the compounds are such that either X is CI CCH and X is (CH C or Xis (CH C and X is The hydrolysis is carried out in a polar organicsolvent, preferably a nitroalkane (lower alkyl) or lower alkyl nitrilesuch as acetonitrile, a source of water and a strong organic acid, suchas p-toluene-sulfonic acid or trifluoracetic acid. It should be notedthat the water may be in the form of a hydrate, such asp-toluenesulfonic acid monohydrate. This reaction may be carried out ata temperature of from about 0 to about C, preferably room temperaturefor from 1 to 24 hours.

It should also be noted that compounds I and Il may also be prepared bya direct hydrolysis of compounds of the formula VI wherein and X are (CHC.

This invention also encompasses the intermediates formed in the processof this invention having the structure:

wherein Z is as previously described-and X is CI CCH (CH;,);,C orhydrogen.

DETAILED DESCRlPTlON The following examples are provided forillustrative purposes and may include particular features of theinvention; however, the examples should not be construedas limiting theinvention, many variations of which are possible without departing fromthe spirit or I EXAMPLE 12,2,2-Trichloroethyl-7-[N-(2,2,2-Trichloroethyloxycarbonyl)-D-a-(1,4-cyclohexadienyl)glycylamido1-3-Methyl3-cephem-4-carboxylate. Solution (A) Methylchloroformate (0.47g, 5 mmole) in 40 ml tetrahydrofuran dried over calcium hydride.Solution (8) 2,2,2trichloroethyloxycarbonyl(1,4-

cyclo-hexadienyl)glycine (1.64 g, 5 mmole) in'20 ml dry tetrahydrofur'antriethylamine (0.4g) dime- PROCEDURE To Solution (A) cooled to 25C,solution (B) is added dropwise with constant stirring (during 15'minutes time). After about 40 minutes of stirring at 25, solu tion (C)is then added dropwise with constant stirring (during 15 minute period).The resulting reaction mixture isthen stirred between 20C to l5C for 3%hours. The mixture is let warm to room temperature and stirred for anadditional half an hour. The solvent is then removed on a flashevaporator and the residue is dissolved in 30 ml ethylacetate; The layeris washed with the following solutions: 2 X 50 ml 8% hydrochloric acid,2 X 50 ml 5% sodium bicarbonate, 2 X 50 ml water and finally with 2 X 50ml saturated sodium chloride solution. The resulting solution is finallydried over anhydrous magnesium sulfate. The solvent is removed on aflash evaporator, and the semi solid obtained is dried at 0.6 mm/Hg(r.t.) overnight, yield mole is almost quantitative. The material iscrystallized from ethyl acetate and pet-ether. A crystalline compound,pale in color 3.8 g; 81 mole yield melting at l45-147C is obtained.

I EXAMPLE 2 Conversion of 2,2,2-Trichloroethyl 7-[N-(2,2,2-Trichloroethyloxycarbonyl )-D-( 1,4-cyclohexadienyl)glycylamidol-3-Methyl-3-cephem 4-carboxylate toCephradine Process A The compound of Example 1 (0.2 g; 0.31 mmole) isdissolved in ml of aq. formic acid at ice bath temperature and to theclear solution thus obtained is added (in several small portions) 1.0zinc dust during a period of 15 minutes. The mixture is stirred at icebath temperature for four hours, thereafter it is filtered under suctionand the residue is washed with 2 X 5 ml 90% formic acid. The combinedfiltrate is concentrated to dryness, and the last traces of formic acidare removed by azeotroping with benzene. The solid residue is dissolvedin 35 ml water, and the undissolved remaining solid is filtered off.ThepH of the solution is ad justed to 2.0 and then H S gas passedthrough the solution until precipitation of zinc sulfide is complete.The mixture after keeping at room temperature for 15 minutes is filteredthrough hyflo. and the filtrate is concentrated on a flash evaporator todryness. The solid residue is dissolved in 15 ml of water and sodiumhydroxide solution. The small amount of precipitateformed is filtered,and the filtrate is adjusted to pH 4.4, and diluted with 3 volumes ofacetonitrile. Stirring of the mixture is continued in an ice bath for 1hour. A solid crystallizes out on seeding with cephradine which isfiltered, washed with 2 X 0.2 ml water and dried at room temperatureunder 0.6 mm/Hg pressure. The colorless product weighs 40 mg; 38.5 moleyield, m.p. 186C l 88C (d).

Process B Thecompound of Example 1 (0.2 g; 0.31 mmole) is dissolved incold 90% aq. formic acid (70 ml). To the clear solution obtained is thenadded with constant stirring in an ice bath (in several smallinstallments) 1.0 zinc dust during a period of 15 minutes. The mixtureis stirred in ice bath for 1 hour. It is filtered under suction, and theresidue washed with 2 X 5 ml 90% aq. formic acid. The combined filtrateis concentrated on flash evaporator and last traces of formic acid areremoved by stripping off with 3 X 20 ml benzene. The solid residue isdissolved in 35 ml water and pH of the solution is adjusted to 2.0.Through this solution is passed H S gas and the zinc sulfidewhichprecipitates is filtered off via hyflo. The filtrate is concentrated todryness, and the residue is dissolved in 35 ml acetonitrile. The pH ofthe solution is adjusted to 8.5 by means of triethylamine, any solidswhich separate out are now filtered. The filtrate is adjusted to pH 6.0by means of 1N HCl. The solids crystallize out on stirring for one hourin an ice bath and are filtered, washed with 0.2 ml of water and driedat room temperature and at 0.6 mm/Hg for 6 hours. The colorless solidweighs 45 mg; mp. l85-l87C (cl). Yield 43 mole EXAMPLE 32,2,2-Trichloroethyl-7-[N-2,2,2-Trichloroethyloxycarbonyl )-D-a-( l,4-cyclohexadienyl )glycylamido]- 3 acetoxymethyl-3 cephem-4-carboxylate According to Example 1, if one uses 7-amino-cephalos poranicacid, trichlorethyl trichloroethyl in place of 7-aminodesacetoxycephalosporanic acid, trichloroethyl ester, the titlecompound is obtained.

EXAMPLE 4 Conversion of I 2,2,2-Trichloroethyl-7-[N (2,2,2Trichloroethyloxycarbonyl )-D-a l ,4- cyclohexadienyl )glycylamido]3-acetoxymethyl-3 cephem-4-carboxylate to 7-[ D-2 -arnino-2-(1,4-cyclohexadie nyl) acetamidolcephalosporonic acid.

The compound of Example 3 is cleaved in the manner described in Example2 to give the title compound.

EXAMPLE 5 2,2,2-Trichloroethyl 7-[N-(t-butoxycarbonyl)-D-( 1,4-cyclohexadienyl)glycylamido]-3-methyl-3-cephem-4- carboxylate MATERIALSSolution (A) Methyl chloroformate (0.4 g) in 65 ml dry tetrahydrofuran.

10 Solution (B) N-t-butoxycarbonyl (1,4-

cyclohexadienyl) glycine DHPG (1.11 g) in 60 ml tetrahydrofurantriethylamine (0.4 g) dimethylbenzylamine (2 drops) Solution (C)7-aminodesacetoxycephalosporanic acid 2,2,2-trichloroethyl ester (2.1 g)in 40 ml tetrahydrofuran.

METHOD To Solution (A) cooled to 25C, solution (B) is added withstirring (during minutes). Stirring is continued between 20C for 40minutes, and then Solution (C) is added with stirring and in a dropwisemanner to the above reaction mixture and then the mixture is stirred at-20.C to -l5C for an additional 3 7% hours. Next the reaction mixture isstirred at room temperature for half an hour. The solvent is removed onflash evaporator, and residue is dissolved in 250 ml of ethyl acetatewhich is washed with 2 X 50 ml 5% hydrochloric acid,

2 X 50 ml 5% sodium bicarbonate solution, 2 X 50 ml EXAMPLE 62,2,2-Trichloroethyl 7-[N-(t-butoxy carbonyl )-D-a-( 1,4-cyclohexadienyl)glycylamido1-3- acetoxymethyl-3-cephem-4-carboxylate According toExample 5, if one uses 7-amino-cephalosporanic acid 2,2,2-trichloroethylester in place of 7- aminodesacetoxycephalosporanic acid 2,2,2-trichloroethyl ester, the title compound is obtained.

EXAMPLE 7 2,2,2-Trichloroethyl 7-[ D-( l ,4-cyclohexadienyl)glycylamido]3-methyl-3- cephem-4-carboxylate The compound of Example 5(1.0 g; 1.7 mmole) is dissolved in ml of acetonitrile. To this solutionptoluene sulfonic acid monohydrate (1.0 g; 5.4 mmole) is added, and themixture stirred at room temperature for 18 hours. The solvent is removedin vacuum, and the residue is dissolved in 80 ml ethyl acetate, thesolution-is cooled and washed with 2 X 25 ml 5% sodium bicarbonatesolution and then with 2 X 15 ml water. The resulting solution is driedand solvent removed under vaccum. The pure product is soluble in dilutehydrochloric acid and is obtained in a yield of 75 mole (0.61 g) EXAMPLE8 The compound of Example 6 is hydrolyzed in the manner described inExample 7 to give the title compound.

EXAMPLE 9 Conversion of 2,2,2-Trichloroethyl 7-[D-( l,4-cyclohexadienyl)glycylamido]-3-methyl-3- cephem-4-carboxylate toCephradine The compound of Example 7 1.3 g; 2.0 mmole) is dissolved in80 ml of 90% aqueous formic acid. The solution is cooled in an .icebath. Zinc dust (1.9 g; 60 mg atoms) is added in several small portionswith stirring, and the mixture is stirred in an ice bath for 1 hour. Thezinc is filtered and washed with 3 X 5 ml 90% aqueous formic acid. Thefiltrate and the wash are combined and evaporated in vacuum. Last tracesof formic acid are removed by azeotroping with benzene. The residue istaken up in 60 ml water and treated with hydrogen sulfide. Theprecipitated zinc sulfide is filtered with the aid of hyflo. Thefiltrate is adjusted to pH 7.2 and a slight precipitate formed isfiltered and the filtrate is concentrated to half the volume. The pH isadjusted to Y 4.0, diluted with 35 ml acetonitrile, and cephradinecrystallized out on stirring in ice bath for 1 hour. It is filtered anddried, weighing 0.72 g, (yield 70 mole EXAMPLE 10 Conversion of2,2,2-Trichloroethyl-7-[D 1,4- gcyclohexadienyl)glycylamidol-3-acetoxymethyl-3- cephem-4-carboxylate tocompound II.

I The compound of Example 8 is cleaved in the manner described inExample 9 to give Compound ll.

EXAMPLE 11 I 7-[N-( t-butoxycarbonyl)-D-( 1,4-cyclohexadienyl)glycylamidol-3-methyl-3-cephem-4- carboxylic acid Thecompound of Example 5 (1.0 g. 1.75 mmole) is dissolved in 50 ml 90%aqueous formic acid. To this solution in an ice bath, zinc dust (5.0 g)is added in several small portions. This mixtureis then stirred in anice bath for 1 5% hours. The mixture is filtered to remove zinc, and thefiltrate is concentrated on a flash evaporator with the last traces offormic acid being removed azeotropically with benzene. The residue istaken up in 20 ml water and 60 ml ethyl acetate, and the mixture 7 isstirred in anice bath. The ethyl acetate solution is washed with 2 X 20ml 5% hydrochloric acid and then with 2 X 15 ml water, dried over MgSOand evaporated. to a semi solid material. This product on examina-EXAMPLE 12 7-[N-(t-butoxycarbonyl)-D-(1,4-cyclohexadienyl)glycylamido1-3-acetoxymethyl-3 cephem-4-carboxylic acidThe compound of Example 6 is cleaved in the manner described in Example1 l to give the title compound.

EXAMPLE l3 Conversion of 7-[N-( t-butoxycarbonyl )-D-( 1,4-cyclohexadienyl)glycylamidol-3-methyl-3-cephem-4- carboxylic acid toCephradine The compound of Example ll (1.0 g; 2.29 mmole) is dissolvedin 60 ml acetonitrile and treated with ptoluenesulfonic acid monohydrate1.9 g; 10 mmole). The reaction mixture is stirred at room temperatureovernight. The solution is cooled and 4 ml of water added and the pHadjusted to 5.2 by means of triethylamine. The stirring is continued for1 hour, and the material which crystallizes is filtered, washed withcold acetonitrile and dried to constant weight. (0.54 g), yield 65.5mole EXAMPLE l4 7 Conversion of 7-[ N-(t-butoxycarbonyl )-D-( 1,4-cyclohexadienyl)glycylamido]-3-acetoxymethyl-3- cephem-4-carboxylic acidto Compound II.

The compound of Example 12 is hydrolyzed in the manner described inExample 13 to give compound II.

EXAMPLE l5 N- (2,2,2-trichloroethyloxycarbonyl)-D-a-( l ,4-cyclohexadienyl)glycine Dihydrophenylglycine (23.0 g; mmole) isdissolved in 300 ml of water and to this suspension is added [60 ml of1N sodium hydroxide solution. To this solution, ether (150 ml) is thenadded. This is designated as S0- lution A. This Solution A is thenplaced in a 3 1. three neck flask and cooled in an ice bath.2,2,2-trichloroethylchloroformate (2.5 g, 200 mmole) is dissolved in 200ml of dioxane (Solution B), and a 1N sodium hydroxide (200 ml) isdesignated as Solution C. Solutions (B) and (C) are added dropwise atthe same time to Solution A with constant stirring, while the mixture iscooled in an ice bath. The addition is completed over a period of 1hour. The reaction mixture is stirred for an additional 1 hour period inan ice bath. The resulting mixture is washed with 2 X 300 ml of ether.The aq. phase is then slurried with 350 ml ethylacetate in an ice bathand acidified to a pH 2.5 with syrupy phosphoric acid. The organic phaseis separated, washed with 2 X 200 ml water and dried over MgSO Thesolvent is removed on a flash evaporator and the residue dried undervacuum (36.5 g) yield 74 mole The material on crystallization from ethylacetate and petroleum ether gives colorless crystals mp. 150C 152C.

What is claimed is: l. A compound of the formula:

utilizing zinc dust and formic acid and hydrolyzing said S productutilizing a strong organic acid and a source of water in an organicsolvent.

| NH 3. The rocess of claim 2 wherein said stron acid 314,2 5 P g C==Qand source of water is p-toluenesulfonate monohyl drate. 0X o 4. Theprocess of claim 3 wherein said organic solvent in the hydrolysis stepis acetonitrile. 5. A process for the preparation of a compound ofwherein Z is selected from the group consisting of hythe formula:

drogen and acetoxy and X is selected from the group 0 consisting oftrichloroethyl, t-butyl and hydrogen. ll 5 CHC-NH 2. A process for thepreparation of a compound of f the formula: 2

I wherein Z is selected from the group consisting of hy- 2( drogen andacetoxy WhlCh comprises hydrolyzmg a N compound of the formula CH,Z

dc-Nu 2- -r wherein Z is selected from the group consisting of hydrogenand acetoxy which comprises reducing a com- 0 N H 2 pound of the formulaO-C(CH=)3 O cH CCl CO,H

utilizing a strong organic acid and a source of water in an organicsolvent and reducing said product utilizing O ll 5 zinc dust and formicacid. T C NH 6. The process of claim 5 wherein said strong acid NH andsource of water is p-toluenesulfonate monohyto i o 7. The process ofclaim 6 wherein said organic sol- O--C(CH;,) co cH cc| vent in thehydrolysis step is afetgnitrile.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION Page1 of 2 It is certified that error appears in the aboveidentified patentand that said Letters Patent a 0 NW} Z CO CH CCl S W o l l o f 1 S a a td e a .1 r s m u m m O 9, S H 6 m l r I. HA N m w 0 1 HH=X U. m C N C O9+..HW C c m In 30 f r n 0 mm m w m c 0. mm M M.DN m e EEE e h MM m TDIDW a O Q UNITED STATES PATENT AND TRADEMARK OFFICE EERTIFICATE OFCORRECTION Page 2 of 2 PATENT NO. I 3 912 72 Q DATED 10/14/75 INVENTORG)2 Patrick Andrew Diassi, et a1 it is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below: it

Col 3 line 3 "p-methoxybenzlamine" should read pmethoxybenzylamine Col.8, line 18, "ptol-" should read p-tol- Signed and Scaled this first DayOf June 1976 [SEAL] Q v Arrest:

RUTH c. mson c. MARSHALL DANN Arresting Officer Commissioner vj'larenrsand Trademarks a;

a," v Mam.

1. A COMPOUND OF THE FORMULA:
 2. A process for the preparation of acompound of the formula:
 3. The process of claim 2 wherein said strongacid and source of water is p-toluenesulfonate monohydrate.
 4. Theprocess of claim 3 wherein said organic solvent in the hydrolysis stepis acetonitrile.
 5. A process for the preparation of a compound of theformula:
 6. The process of claim 5 wherein said strong acid and sourceof water is p-toluenesulfonate monohydrate.
 7. The process of claim 6wherein said organic solvent in the hydrolysis step is acetonitrile.